Comment on Trendler’s (2019) “Conjoint measurement undone”

Abstract

Most of Trendler’s (2019) article, “Conjoint measurement undone,” seems wrong to us. We explain why we disagree completely with two of his assertions: (a) that cardinal measurement scales are absent in psychology and (b) that psychology has stagnated. We share three of his other concerns, but not his perspectives on them or the supposed links among them. These three points are: (a) fewer applications of additive conjoint measurement than initially expected, (b) flaws in the practice of statistics, and (c) need to improve the culture of replication in psychology. We provide our views on these points and also note two distinct strands in the foundational analysis of measurement—one derived from geometry, the other from probability. Trendler completely overlooked the latter.